Ethylene serves as a gaseous growth hormone for plants. It acts at trace levels throughout the life of the plant to stimulate or regulate the ripening of fruit, the opening of flowers, the shedding of leaves, and other plant functions. In particular, ethylene can stimulate fruit ripening in apples, induce pineapple flowing, hasten the coloring of harvested lemons, or inducing shedding of tree leaves prematurely. In many cases, ripening fruit and other plants produce large amounts of ethylene gas that can adversely affect plants surrounding the ripening fruit or plants. Ethylene has been identified as a natural product of not only fruits but of many other parts of plants, including leaves, stems, flowers, roots, tubers, and seedlings. The rate of ethylene production depends on both the type of plant tissue and its stage of development.
Premature ripening and degradation of plants caused by ethylene can interfere with productive use of those plants and is a major problem in the many industries involved in plant preservation. Ethylene can cause significant economic loss for florists, marketers, suppliers, shippers, and growers. In the field of produce transportation, for example, ripening can cause a decrease in shelf life of the transported produce resulting in a decrease in sales volume. In the field of cut flowers and potted plants, ethylene production can reduce shelf life and useful life after a sale. Studies have shown that removal of a portion of the ethylene from a gaseous environment can lower the spoilage rate of the plant materials
In the cut flower industry a spoilage rate is associated with the amount of time that flowers can be used before spoilage. An average shelf life of ten to fourteen days, in refrigerated storage, exists prior to the commencement of deterioration beyond industry standards for retail sales. In addition to the shelf life before the retail sale, cut flowers must not deteriorate for a certain amount of time after the retail sale. Typically, industry standards require that the flowers not deteriorate for at least five days after the retail sale. Deterioration of cut flowers is judged by the more delicate outer leaves which are first to deteriorate. As a result, a reduction in the amount of ethylene that comes in contact with cut flowers is of utmost importance to the cut flower industry.
A need exists to extend the useful life of plant materials like cut flowers by removing ethylene from storage containers. Also, in the industry of organic foods, the spoilage rate tends to be more rapid due to the lack of food preservatives. Nothing can be added to organic foods or plants to prevent rapid ripening because such additives are not permitted to organic foods. A large need exists in the organic food industry to reduce the amount of ethylene that comes in contact with organic foods without adding to or altering the organic foods.
Problems can arise when ethylene producing commodities and ethylene sensitive commodities are transported or stored together. For example, high ethylene producers (such as ripe bananas, apples, and cantaloupe) can induce physiological disorders and/or undesirable changes in color, flavor, and texture in ethylene sensitive commodities (such as lettuce, cucumbers, carrots, potatoes, and sweet potatoes). Thus in the industry of food transportation, there exists a strong need to reduce the amount of ethylene that remains near transported foods. Due to the spoilage rate in each of the above mentioned industries and many more industries, there exists a very strong need to increase the shelf life period of the various plant materials by reducing the amount of ethylene that comes into contact with the plant materials.
A need also exists for a method of removing ethylene from a storage environment that is not based on breaking down the ethylene into carbon dioxide and water. Breaking down ethylene into carbon dioxide and water has major drawbacks. For example, breaking down ethylene into carbon dioxide and water requires expensive equipment with a high cost of installation. Additionally, there is a high cost of operating such systems due to energy needs and repair costs. A need exists for an inexpensive method that is not based on breaking down the ethylene but rather traps ethylene so that it can be removed from the gaseous environment.